Retrieve Linux command line history by date

Question

I want to see what I typed on my bash command line on a certain day a week ago. Is there a way to retrieve command line history? Something like below, perhaps?

> history --include-date | grep 2012-02-27`

Solution

By default, History logs the time when you ran a command, but doesn't display it. The reason for this is when you run the History command, it looks for an environment variable called HISTTIMEFORMAT, which tells it how to format time. If the value is null or not set, then by default it doesn't show any time.

An example with some time-

[qweet@superbox ~]$ export HISTTIMEFORMAT='%F %t '
[qweet@superbox ~]$ history
    1  2012-03-06        su -
    2  2012-03-06        [email protected]
    3  2012-03-06        mysql
    4  2012-03-06        ll
    5  2012-03-06        cd /opt/
    6  2012-03-06        ll
    7  2012-03-06        exit
    8  2012-03-06        ll
    9  2012-03-06        ls -lsa
   10  2012-03-06        cd ../
   11  2012-03-06        ll
   12  2012-03-06        ll
....

But that's not all. Since the HISTTIMEFORMAT takes strftime values (which you can find here btw), you can do all sorts of magical things. But for what you want to do, the following works.

[qweet@superbox ~]$ export HISTTIMEFORMAT='%F %T %t'
[qweet@superbox ~]$ history | grep -e "2012-03-06 14:48"
 1006  2012-03-06 14:48:05      export HISTTIMEFORMAT='%F %T %t'
 1007  2012-03-06 14:48:07      history
 ...

Also, if you want your HISTTIMEFORMAT to persist, consider appending it to your bashrc like so;

echo 'HISTTIMEFORMAT="variables here"' >> ~/.bashrc

You will see the changes when you open a new tab in the terminal, or logging out and in.